Standard local (Richter) magnitude
ML is the standard local (Richter) magnitude originally designed for Southern California by :cite:t:`richter-1935`.
The ML amplitude calculation is similar to the original ML. Waveforms from both horizontal components are time-windowed and restituted to the Wood-Anderson seismograph. Within the time window the amplitudes are measured on both horizontal components and combined. The methods for measuring and combining amplitudes are configurable in the global bindings.
The individual station ML is calculated using the following formula:
A is the measured ML Wood-Anderson amplitude in millimeters. The second term
is the empirical calibration function, which in turn is a function
of the epicentral distance (:cite:t:`richter-1935`). This calibration
function and distance range can be configured globally or per station using global
bindings or the global module configuration variable
module.trunk.global.magnitudes.ML.logA0 = "0 -1.3;60 -2.8;100 -3.0;400 -4.5;1000 -5.85" module.trunk.global.magnitudes.ML.maxDistanceKm = "-1"
The logA0 configuration string consists of an arbitrary number of distance-value pairs separated by semicolons. The distance is in km and the second value corresponds to the log10(A0) term above.
Within each interval the values are computed by linear interpolation. E.g. for the above default specification, at a distance of 80 km the log10(A0) value would be
In other words, at 80 km distance the magnitude would be
which is according to the original Richter (1935) formula if the amplitude is measured in millimeters.
Several distance-value pairs can be configured for different ranges of epicenter distance.
Amplitude unit in SeisComP: millimeter (mm)
Time window: 150 s by scautopick or distance dependent, configurable
Default distance range: 0 - 8 deg, maximum is configurable:
magnitudes.ML.maxDistanceKm, measurements beyond 8 deg will be strictly ignored.
Depth range: 0 - 80 km, configurable for amplitude measurements
By default, the mean is calculated from the station magnitudes to form the network magnitude.
Set the configuration and calibration parameters in the global bindings similar to MLv.
Instead configuring lots of global bindings profiles or station bindings one
line per parameter can be added to the global module configuration (